Auger or bit



April 1931- c. HARDSOCG 1,803,183

AUGER OR BIT Original Filed July 16, 1926 Patented Apr. 28, 1931 UNITED STATES PATENT OFFICE (LBLBDBOGG, 0F IOWA, ABSIGNOB 1'0 HABDBOOG MANUIAOT'UB- DIG COMPANY, 0] (HTML, IOWA, A CORPORATION 01' IOWA.

AUGEB OB BIT Original application fled J'uly 16, 1928, Serial Io. 122,988. Divided and this application illed December 81, 1920. Serial Io. 158,359.

This invention relates to a drill or auger particularly designed for drilling blast holes in coal mines and also for other purposes, and embodies a division of my apphcation Serial 5 No. 122,929. filed July 16, 1926, and relating particularly to a removable head having a novel arrangement of bits as a part of the structure of drill disclosed by my said application.

The object of the present invention is to provide an auger with a removable head havmg an advantageous arrangement of removable bits and means for carrying the opposing groups of the bits in eflective penetrating 15 and cuttmg positions, and also to reinforce the bits against breakage by backing the same at a oint intermediate of their lengths.

A rther object of the invention is to generally improve the construction and arran ement of the bit construction of an auger oft e type specified.

With these and other objects and advantages in view, the invention consists in the preferred construction and arrangement of g the several parts which will be more fully hereinafter described and claimed.

In the drawings:

Fig. 1 is an elevation of a portion of a spiral au er shank or conveyor with the removable ead applied thereto in o rative position and provided with separa le bits, all of which embody the features of the invention.

Fig. 2 is a to plan view of the removable head, showing t e hits at the lower extremity thereof partially in full and dotted lines.

Fig. 3 is a bottom plan view of the removable head.

Fig. 4 is a transverse section on an enlar scale through a portion of one of the itholding members, showing one of the bits therein and articularly illustrating the bracing or bac 'ng feature.

The numeral 5 designates an auger or drill shank which may be of any desired len h and of spiral or twisted form, and remova 1y associated with the lower extremity of the shank is a cutter head 6, which is also of spiral or twisted form, and continuous with the lower extremity thereof is a dual bit member 7. The lower extremity 8 of the splral or twisted auger or drill shank is contmued 1n the same form and dimensions as the main body of the shank above the same, and m the upper extremity of the removable head 6 is a spiral socket 9, as shown by dotted lines in Fi 1 and in top plan view by Fig. 2, and in t is socket the lower extremity 8 is fitted by giving it a screwing movement. By this means there is no reduction in dimensions of the said lower extremity 8 of the shank 5 and as a consequence there will be no weakening of this part of the shank. The spiral type of socket just explained allows t e cuttlngs to be conveyed with little or no restriction and eliminates the necessi of adding metal to the upper end of the head and a mmimized projection of the structure at the upper end of the head and a consequent reduction of resistance to the free 0 eration of the assembled head and shank. fn the spiral form of removable head and shank as heretofore adopted, the lower extremity of the shank was materially reduced and the socket in the upper portion of the head formed in an increased dimensional structure provided by adding metal to the upper extremity of the head. In this previous form of shank and removable head, considerable projection was provided at the joint, which caused the cuttings to clog the socket and obstruct the free action of the auger as a whole. The present spiral type of joint, or the spiral socket 9 in the upper portion of the removable head 6 and the continuation of the lower extremity of the shank 5 in spiral form and of a width equal to the shank a ove, permits attachment of the auger shank or conveyor to the head without welding a supplemental shank or tenon device to the end of the main shank. Practical experience has shown that nearl all .breakages occur just back of the or inary form of square shank used in this type of an er comprising a main shank and removab e cutter head, the break being efiected where the spiral twist commences, and very seldom if ever does the spiral shank break at any other point.

The present improvement is therefore particularly intended to overcome the disadvantages heretofore experienced in prior similar devices during drilling operations. The lower extremity 8 of the shank 5, when fitted in the socket 9 by screw action as heretofore explained, is held against loosening and displacement by a transverse pin 10 inserted through the associated gearts. If found necessary, the pin may a removed and the shank 5 and head 6 readily separated by a screwing movement reverse to that necessary to insert the lower extremity 8 within the socket 9. In the type of auger or drill as heretofore constructed comprising a removable head, it was usually necessary to weld a slug of steel to the end of the auger and forge it down to fit the socket in the head in order to provide the supplemental shank projection or tenon, and this method often resulted in the burning of the steel and creating a weak point where the spiral terminated and the supplemental reduced shank, usually of square form in cross section, began. In order to have a socket of suflicient strength to withstand the strain, it is necessary to have a wall surrounding the shank at least threesixteenths to one-fourth of an inch thick, and this increase of dimensions at the joint renders the joint structure, particularly at the upper end of the head, very large with the disadvantages hereinbefore specified.

In the improved form of oint embodying the features of the present invention the removable cutter head casting is cored out spirally, so that the auger screws into it, and by this means the walls of the casting forming the socket may be materially lighter and of the same general shape as the conveyor, which will lessen the liability of clogging with cuttings.

further feature of improvement in the present anger or drill is the means for supporting and reinforcing the cutter bits car- .ried by the bit member 7 The bit member 7 comprises two oppositely positioned and reversely extending bit carriers 11 and '12 connected by a substantially transverse reduced neck or web 13. Each carrier is formed with an inner cut-away portion 14, which provides a depending shoulder 15 and a curved base 16 with which the shoulder intersects at right angles. From the shoulder outwardly an increased thickness of metal is provided, and each shoulder also tapers from a substantially straight wide terminal 17 to a blunt point 18, the outer periphery 18 being regularly curved as shown by Fig. 3. The formation of the carriers 11 i and 12 and the contour thereof is precisely the same, but the blunt point 18 of the carrier 12 and the substantially wide terminal wall 17 are in reverse positions relatively to the corres onding point and wall of the carrier 11. traight sockets 19 are formed in the base 16 of the angular shoulder 14, and in these sockets bits 20 of an lar form in cross section and curved longitu inally are inserted, the enlarged extremities 21 of the bits entering the sockets 19, and owing to the formation of the sockets which are square, and of the portions 21 of the bit shanks inserted in the said sockets, a frictional binding action is set up particularly in view of the longitudinal curve of the said bits 20. The outer backings or shoulders 15 en age the outer sides of the bits20 at points eyond or at a distance below the inlets of the sockets 19, and by this means the bits are reinforced and held positively against bending or fracture, all as clearly shown by Fi 4.. The bits 20 will be prevented from falling out of the sockets 19 in view of the longitudinal curvature thereof and the straight formation of the said sockets, and when the said bits are arranged in the sockets, they will be given the proper reversely inclined positions in the two carriers or at opposite sides of the member 7. When the bits 20 are inserted in their sockets 19, they are forced with considerable pressure until fully seated, and if necessity requires removal of any of the bits, they are withdrawn from their sockets by means of a suitable tool. The bit member 7 is of the same diametrical extent as the spiral portion of the head 6 above and only slightly larger than the auger or drill shank 5 separa 1y connected to the said head.

The spiral socket 9 together with the spiral formation of the lower extremity 8 of the auger 5 which is fitted into said socket by a.

screwing action as hereinbefore explained provides an exceptionally strong joint with various points of pressure resistance owing to the spiral formation of the socket and the said lower extremity 8. This spiral forma-' tion of the socket 9 and the lower extremity 8 of the shank 5 also sets up a further resistance to a straight withdrawal of the extremity 8 from the said socket, and moveover, the

said spiral extremity 8 and socket 9 more.

evenly distribute the strain imposed upon the joint during rotation of the auger .or drill in performing its function, and this distribution of strain together with the increase in dimensions of the extremity 8 and the socket- 9 relatively to devices of this character as heretofore constructed will materially increase the obstruction to breakage of the said extremity and give a decided advantage in rotating the head 6 with its bit member 7 at the lower extremity of said head.

It will also be seen that the positions of the carriers 11 and 12 on op osite sides of the center 'of the lower end 0 the bit member 7 together with the groups of bits, consisting of three in each group in the present instance, will provide for a more effective cuttin action of the bits. The bits of each roup ave their reduced extremities rojecte inwardly relatively to the bottom of the bit member 7 and in view of this reverse position of the bit groups and the neck 13 an unrestricted clearance for the borings is provided, the borings passing over the outer surface of the bit member 7 through the opposed grooves 22.

The shank 5 and head 6, in view of the foregoing screw association of these parts, will be sufiicient under certain conditions to hold the two parts in connected relation without 10 any other means, and as a consequence the pin 10 or analogous device may be omitted.

What is claimed as new is: A drill head provided with a substantially straight socket, in combination with a bit longitudinally curved substantially through.- out its length and because of its curvature having binding retaining engagement in said socket, and said head having a shoulder portion projecting beyond the entrance to said socket and disposed in supportin contact with a face of the bit outwardly of the socket. In testimony whereof I have hereunto set my hand.

LESTER C. HARDSOCG. 

